hp-oj-5510 243 stefan [24/Apr/2012:10:36:05 +0200] 1 1STATE: - localhost xy-file-46 - -
hp4p 244 stefan [24/Apr/2012:10:38:33 +0200] 1 1 - localhost Unbenannt1 - -
hp-oj-5510 243 stefan [24/Apr/2012:10:39:09 +0200] 2 1INFO: - localhost xy-file-46 - -
hp-oj-5510 246 stefan [24/Apr/2012:10:40:28 +0200] 1 1STATE: - localhost xy-file-46 - -
hp-oj-5510 246 stefan [24/Apr/2012:10:43:37 +0200] 2 1INFO: - localhost xy-file-46 - -
hp-oj-5510 247 stefan [24/Apr/2012:10:43:50 +0200] 1 1STATE: - localhost Unbenannt1 - -
The file on hp4p wasn't printed, and I don't know details of the file-format.
But the cups webinterface has a section
jobs and therein
completed jobs, (translated from german - the words may differ).
The link goes to localhost - maybe your server is running on a different machine. Unfortunately the filename is only given without path, but with locate, it might in many cases be possible, to reconstruct which file was printed.